1. Field of the Invention
The present invention relates to improving the reliability of high reliability systems. More specifically, the present invention relates to identifying connections of uninterruptible power supplies to system resources.
2. Description of the Related Art
High reliability is often required in mission critical applications such as those that occur in medical, financial, communication, and military systems. Such systems can become very large and complex, involving numerous sub-systems that are integrated together by complex interconnections. For example, computer systems that process financial data can involve racks of hardware and can include hundreds of sub-systems, each with its own processors and power supplies. Another example is an Internet communication system that is comprised of numerous distributed servers. Such systems usually include a service processor that controls and integrates the individual sub-systems together under the direction of operating software.
Reliability can be so important that some systems have sub-systems with redundant power supplies that are connected to different power lines which are fed by different circuit-breakers. Other applications, e.g., communication servers, distribute user demands over distributed networks that are powered by different power lines that pass through different circuit breakers. Some applications are so critical that the different circuit-breakers are themselves powered by different power companies. When reliability is important the use of uninterruptible power supplies (UPS) is common. A UPS provides backup power in the event of an electrical outage or other power line disturbance. A UPS usually includes a battery system that powers an inverter that supplies operating power to the protected system or sub-system. The UPS can either power the system or sub-system only when a failure occurs or it can power the system or sub-system continuously with the input AC power acting as a re-charger for the batteries.
Some dual-power line systems use only one UPS that is fed from one AC power line. In such cases the other AC power line is directly connected to the other power line. In other dual-power line systems, each AC power line connects to a different UPS. Either way, to maintain reliable operation it is important to ensure that each of the redundant power supplies is powered by a different AC power source. Otherwise, the purpose of having dual-power lines is defeated. In distributed system many different sub-systems are often connected to the same UPS. If that UPS fails those sub-systems can be brought down.
What the foregoing systems have in common is a need for high reliability and the use of UPS systems to assist that reliability. However, no matter how reliable any power source is, it can fail. For example, if input power is removed from a UPS, eventually the UPS battery will fail. If dual-lines are feed from different circuit breakers powered by the same power company, the power company can fail. If different power companies are used, an electrical grid malfunction can shut-down both power companies.
While input power cannot be guaranteed, it is possible to provide controlled shut-down of systems to prevent, reduce, or mitigate problems. To improve reliability and/or to assist controlled shut-down it can be very useful to know what system resource is being powered by any particular USP system. Then, when that UPS has a problem or signals that a power failure may occur the service processor can perform a controlled shut-down of impacted resources. Unfortunately, determining what system resource is connected to a particular UPS becomes increasingly difficult as the number of UPS and system resources increase and as the system become more and more distributed. Complicating the problem is the desirability of determining which system resource is ultimately connected to a particular AC power line in a dual-line system. Further complicating the problem is providing sufficient time for a system to perform a controlled shut-down of system resource prior to power failure.
Therefore, techniques of identifying which system resource is connected to which UPS would be useful. Information that can be used to ensure that redundant power supplies are operatively connected to different UPS devices and to different AC power lines also would be beneficial. Also beneficial would be techniques of determining which system resources are powered by which UPS and which AC input line. Also beneficial would be a method of ensuring that sufficient notice is given before a particular system resource fails to provide for a controlled shut-down.